#11 Alternative solution that is cleaner, simpler, and less expensive

[shayanushani]

SELECT
s.Manager,
DATE_FORMAT(i.call_date, '%Y-%m-%d %H') Hr,
COUNT(*) as cc
FROM Issue as i
left JOIN Shift s on date(i.call_date) = s.Shift_date
WHERE
(s.Shift_type = 'early' AND hour(i.call_date) <= 13 OR s.Shift_type = 'late' AND hour(i.call_date) > 13)
and (date(i.call_date) = '2017-08-12')
GROUP BY
1,2
ORDER BY
1 desc
;

[Maduka-Vinod]

SELECT
s.Manager,
DATE_FORMAT(i.call_date, '%Y-%m-%d %H') AS Hr,
COUNT(*) AS cc
FROM Issue i
LEFT JOIN Shift s
ON DATE(i.call_date) = s.Shift_date
WHERE
(
(s.Shift_type = 'early' AND HOUR(i.call_date) <= 13)
OR
(s.Shift_type = 'late' AND HOUR(i.call_date) > 13)
)
AND DATE(i.call_date) = '2017-08-12'
GROUP BY s.Manager, Hr
ORDER BY s.Manager DESC;